STL Sample for the set::count Function

Last reviewed: October 9, 1997
Article ID: Q158574

The information in this article applies to:

The Standard C++ Library included with: - Microsoft Visual C++, 32-bit Edition, version 4.2

SUMMARY

The following sample code illustrates how to use the set::count STL function in Visual C++.

MORE INFORMATION

Required Header

   <set>

Prototype

   template<class _K, class _Pr, class _A>
   class set {
   public:
   // Function 1:
      size_type count(const _K& _Kv) const;
   }

NOTE: The class/parameter names in the prototype may not match the version in the header file. Some have been modified to improve readability.

Description

The count function is used to determine the number of elements in the controlled sequence that have a particular key.

Sample Code

//////////////////////////////////////////////////////////////////////
//
// Compile options needed: -GX
//
// SetCount.cpp:
//      Illustrates how to use the count function to determine how
//      many elements have a particular key.
//
// Functions:
//
//    count        Returns the number of elements in the controlled
//                 sequence that have a particular key.
//
// Written by Derek Jamison
// of Microsoft Technical Support,
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
//////////////////////////////////////////////////////////////////////

#pragma warning(disable:4786)

#include <set>
#include <iostream>

typedef set<int,less<int>,allocator<int> > SET_INT;

void truefalse(int x)

{

  cout << (x?"True":"False") << endl;

}

void main() {
  SET_INT s1;
  SET_INT::_Pairib pib;
  cout << "s1.insert(5)" << endl;
  pib=s1.insert(5);
  cout << "Inserted element: ";
  truefalse(pib.second);  // True

  cout << "s1.insert(5)" << endl;
  pib=s1.insert(5);
  cout << "Inserted element: ";
  truefalse(pib.second);  // True

  cout << "s1.insert(8)" << endl;
  s1.insert(8);

  cout << "s1.insert(12)" << endl;
  s1.insert(12);

  cout << "s1.count(5) returned ";
  cout << s1.count(5) << endl;    // 1

  cout << "s1.count(9) returned ";
  cout << s1.count(9) << endl;    // 0
}

Program Output

s1.insert(5) Inserted element: True s1.insert(5) Inserted element: False s1.insert(8) s1.insert(12) s1.count(5) returned 1 s1.count(9) returned 0

REFERENCES

Visual C++ Books Online: Visual C++ Books; C/C++; Standard C++ Library Reference

Additional query words: STL STLSample count string
Keywords : STLIss kbcode
Version : WINNT:4.2;
Platform : NT WINDOWS
Issue type : kbhowto

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Last reviewed: October 9, 1997
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